At five weeks old, South African lion cubs Victor and Isabel are normal, healthy, lively, and – like any baby cat – adorable. But these pint-sized predators came into the world in a unique way: they are the first lions to be born following artificial insemination.

The male and female siblings’ conception was shepherded by veterinarians and mammal specialists from the University of Pretoria (UP), in collaboration with the Ukutula Conservation Center (UCC) & Biobank: a research institute and private game reserve. Victor and Isabel’s mother and sperm-donor father are residents at the facility.

The pregnancy capped off 18 months of study into the lion reproductive system (a lion gestation period is about 110 days). During that time, there were several failed insemination attempts, yet once the proper protocol was determined, the process was simple, Professor Andre Ganswindt, director of the University of Pretoria's mammal research, told AFP.

Happily, the cubs are thriving, but not everyone is happy about the method used to bring their existence about, or how it could be potentially misused. 

According to AFP, a group comprised of 18 African and international conservation organizations wrote a letter addressed to the UP and UCC scientists citing concerns that the technique will be used to breed captive lions for tourism. Their skepticism stems, in part, from the fact that lions already procreate readily in zoos and wildlife parks – so, why is there a need to boost their reproductive efficiency? 

"The captive lion breeding industry in South Africa is exploitative and profit-driven," Mark Jones of the Born Free Foundation told the outlet.

"It generates its income through interaction activities (lion cub petting and lion walks), canned trophy hunting of lions, and the lion skeleton trade while contributing nothing to lion conservation."

The UCC's lion program has been accused of such tactics in the past.

Experts do acknowledge, however, that artificial insemination could help preserve the genetic diversity and birth rates of other wild cat species – like the cheetah – that are more threatened and/or struggle to reproduce in captivity.

African lions usually have no problem breeding in captivity, but wild populations suffer from fragment geographic isolation, which can lead to inbreeding. The IUCN recommends establishing captive breeding programs before wild populations become too small or genetically bottlenecked to be sustainable.

Lions are currently listed as vulnerable on the IUCN Red List, a status they have maintained for many decades. The conservation agency’s most recent assessment, released in 2016, explains that the total lion population has reduced by approximately 43 percent over the past 21 years. However, the level of declines has varied widely across the species’ range. The once widespread Asian subspecies has been reduced to a single population in India, and the African subspecies has become critically endangered or regionally extinct in several areas of West and Central Africa. The South African population is considered least concern.

In a statement posted shortly after the cubs’ birth on August 25, the UCC and UP team explained that this insemination was undertaken as research on "the development of artificial insemination protocols for this species, which could be used as a baseline for other endangered large wild felids.” So, controversy aside, it's good news all round that these little fluffballs are doing so well.